


The Cost of Trust

by magnusbicon



Series: Post 3x10 Fics [3]
Category: Shadowhunters (TV)
Genre: Angst, Childhood Memories, Coda, Episode: s03e10 Erchomai, Introspection, M/M, Mild Blood
Language: English
Status: Completed
Published: 2018-05-22
Updated: 2018-05-22
Packaged: 2019-05-10 00:09:54
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 966
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14726234
Author URL: https://archiveofourown.org/users/magnusbicon/pseuds/magnusbicon
Summary: “My offer still stands. You may have made a life for yourself among the mortals, but you will always be the son of a prince of hell.”





	The Cost of Trust

“I never should have come.”

In all of the centuries he’d been alive, Magnus had never been so angry with himself. He had known all of the risks, had known exactly how his father worked. He was a master of manipulation, warm one minute and scorching hot the next, always ensuring the damage he inflicted upon Magnus was small enough not to kill but significant enough to scar. He had left permanent marks on Magnus’ mind, memories and images that he could not erase no matter how much he wished he could.

Asmodeus’ face contorted in indignation as Magnus turned away from him, and his voice rang through the tense air between them. “Say what you will about the time we spent together. You have to admit, you enjoyed every minute of it.”

“I was a _child_ ,” Magnus immediately replied, the words ripping from his throat and bringing tears to his eyes, and just like that everything was flooding back into the front of his brain, standing at attention in a way that he couldn’t avoid.

 _He watched the blood soaking into the pavement, how it moved ever so slowly across the concrete, stretching out farther and farther as it seeped from his latest victims. His entire body trembled with terror, sick to the bone from what he had done, what his father had_ made _him do. He stood there for hours, abandoned by the one person who was supposed to care for him, and with every rattling breath that he pulled into his lungs his anger blazed brighter. He had followed his father’s every wish and command, done his bidding over and over again with little question, and all it had gotten him were nightmares that left him drenched in sweat and gasping for air._

_So many lives, taken by his own hands._

_When Asmodeus had first approached Magnus, he had felt a sense of relief that he’d been missing for months in the wake of his mother’s death and what he had done to his stepfather. He had looked into those eyes and seen everything he needed in the way they glowed, had taken comfort in the knowledge that he was mistaken in thinking he was alone. But as time went on, Asmodeus’ requests became more and more demanding, more and more violent, and Magnus began to wonder what all of it was for, and why he was letting himself be used as his father’s personal hitman._

Abomination.

_The word sounded in his mind like an alarm, causing his head to throb with the pressure. If his stepfather had been wrong before, he wasn’t now. Magnus had done more than enough to warrant that label, to warrant the hatred of hundreds of people he didn’t even know. He had killed innocent men and women, ripped them from their families with no regard for all of the havoc he left behind. There was no coming back from that. There was only pushing forward through the shame._

_His thoughts continued to spiral as he recounted everything he’d done at the request of his father, every ounce of innocence that he’d given up and every drop of blood that had been spilled because of it, and by the time the sun rose he had decided._

_He was going to banish his father, and he was going to make sure he never saw him again._

He had gone back on that promise to himself, after staying strong for so many years, and now he was going to pay for it, he was sure, but he couldn’t stop. He had to make this deal, if not for Jace’s sake, then for his own. Guilt had been eating away at him for days, churning his insides as he tried to reconcile what he had done. It wasn’t like before. It wasn’t intentional, but it didn’t make it right. He had known something was off the second Lilith stepped into the loft, but he had ignored his instinct out of pity.

He had told Alec he would do whatever it took, and he would.

“Father,” he breathed out, shaking his head and stepping towards Asmodeus once more. “I’ve never once come here to ask you for anything. There must be something _else_ I can give you.” He watched as the corner of Asmodeus’ mouth curved up, clenched his fists as his father tilted his head, and braced himself for what was to come.

“Actually, my son, there is.”

Magnus listened intently as Asmodeus stated his demands, trying to ignore the bitterness that rose in his throat at the sight of his father’s smug grin. His pulse was racing but his mind was frustratingly clear as he felt his magic begin to exit his body. He grit his teeth against the sting that resonated in his skin, and he had to hold back a sob as the last of it drained out of him. His father took a deep breath, his grin wide and content, and waved his arm. Magnus felt some power transfer back inside of him, thrumming in his chest urgently.

“With this you will be able to fulfill your task,” Asmodeus drawled. “You can go back to your precious nephilim, now.” Magnus froze, his mind reeling as he tried to remember ever bringing Alec up in the short time he had been there, but he didn’t have time to dwell on it as his father stepped close.

“My offer still stands. You may have made a life for yourself among the mortals, but you will always be the son of a prince of hell.”

Between one blink and the next Magnus was stumbling back onto New York pavement, his brain screaming for him to finish what he had started and his heart longing for what he had given up.

**Author's Note:**

> I'm on tumblr as magnusbicon!


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